Fixed test isolation problems and updated test libs

It is now possible to:

1) Use the latest JUnit (4.11) which uses a different test ordering to past JUnit versions.
2) Run the test suite on Java 7, which results in a different test ordering than Java 6 when using any past version of JUnit (reflection based ordering mechanism).

eXist Dev's, it must be remembered - 

1) Each test must be atomic and not rely on any other test!
2) Atomic tests may be run in any order!